OH HAI!

First off IF YOU ARE GOING TO DOWN VOTE SAY WHY IN COMMENTS. This why I can either tell you why you are wrong or I can learn something.

I really dislike it when people write guides and state their opinion as a fact so I try to back up what i say with numbers or at very least sound logic where math isn't applicable.

This guide is my attempt to make Cho'Gath into more than just an unkillable tank but also a tank that makes you pay for ignoring him to go after softer targets in a team fight.

Although Cho is probably the hardest champ to take down I found that I was being ignored in team fights and couldn't really do anything but tickle people with my spikes after my spells where used.

I noticed that pretty much every guide on here that to gain damage by getting an AP item with some survivability stat. I found his damage to still be pathetic and the AP didn't solve the problem of being impotent when your spells were on cooldown.

This is a loose guideline, if you want to throw some earlier points into rupture go for it.
Your Q and W get almost their max effectiveness as CCs with just 1 level.
They don't get any CDR with level.
W actually goes up in mana cost per level.

Summoner Spells

Flash I almost always run with this since it sets up your imitation as a tank. Cho doesn't have the dash that just about every other tank in the game has to initiate and this fill the gap. (Powerball,Bandage Toss, Unstoppable Force, Shadow Dash).
With this you can flash to your feast target and in the confusion as they panic and try to run you can almost always land your Rupture on them
Flashing into a group and using Randuin's Omen is also a great way of initiating a fight while laying down massive amounts of cc when combined with your Feral Scream. Between these two you really shut down the enemy's ability to deal damage, or even move.

GhostGreat for escaping or getting to a team fight before it's too late.

ExhaustShut down an enemy carry or slow them making sure you land your rupture. Between the exhaust and rupture that guy isn't going anywhere fast and this can allow your team to catch up or escape.

TeleportAlways a good spell when used effectively. Not my favorite on cho since he is terrible at backdooring but still is a huge help in map presence.

Much better than people make it out to be.
This adds a massive amount of damage to you auto attack in a frontal aoe which when played right can give you the damage to make the other team pay for ignoring you to try to kill your team.

This also works really well with your passive early lane phase to keep up your mana and HP along with giving you a little harassment if aimed properly

Once you hit level 6 stack this by feasting minions as much as possible. The HP increase from ranks is added automatically when you skill it up.

This works really well with flash to get a big nuke off on the target of your choice and put pressure where its needed.

Don't be stingy with this, yes you can KS with it but sometimes it's best to take out a huge chunk of HP so your team and focus down a low hp enemy.

Item Build Reasoning

[builder=Cho'Gath/99b4f51b647504c7455456f83a90e045]
or
[builder=Cho'Gath/6d36ce091a54d8e060b325ee4f5c7627]
If you hate Warmog's or feel like you wont be able to charge it. This is lower EHP and you lose your aura but you don't have to charge and it gives you more the AOE.

Simply put this is the most effective HP I could find while using Nashors.

Since its hard to factor in the feast HP it's kinda hard to do this correctly so if someone finds something better please let me know.

Nashor's Tooth(See cho damage math)Even with 1 damage item Cho'gath is massively tanky, you can look at this builds effective hp vs other tank builds to see how it stacks up.

[item=Force of Nature]:Gives speed boost and MR. The regen effect actally does a whole lot on a champ with this much HP combined with the hp/5 from all the other items.

Better than Banshees and quicksilver because cho can tank the hits, the higher MR works better for him. On top of that the speed makes up for Chos slowness and the regen works very well with his massive HP.

Randuin's Omen:Gives the armor a little bit of HP and an AOE slow with a long duration.

Frozon heart is a good option vs a team with lots of AD but because I take Nashors so much of the CDR is wasted I choose not to get this.

Better than Thornmail because if you are getting beat on by melee it means your team is already dead or the other team is dumb.

Warmog's ArmorMassive HP while cho already has huge HP this item when stacked is still too good not to take. This item use to not be worth it but since it was buffed its not very underrated.

You always get this after your big resists items.

If you don't like warmogs or feel that you wont be able to effectivly charge it another good option is to replace it and aegis with sunfire cape and banseehs veil.

Rylai's

[item-Rylai's Crystal Scepter] This use to be a whole lot more effective on cho when it had its full slow applied to vorpal spikes.

After playing around with it I do find that it is worth getting when your team lacks slows. Being able to constantly slow the other team in your spike aoe can make a big difference.

This becomes less necesary when you have other champs on your team with slows or rylai's or frozen mallet.

Runes

Greater Mark of Alacrityx9
Cho has the highest base damage of any champ I've seen, plus Vorpal Spikes. This makes AS a great choice for actually making him into more than just an ignorable meat shield.

Also lets face it, defensive marks all suck since they have such low stats.

Greater Seal of Clarity
This one is debatable, It allows cho to be more aggressive with rupture. The reason why I take it is because there are very few tank items with mp5 and no options that I really like.

Greater Quintessence of Swiftness
I take at least 1 of these because at level 1 it boosts you from 315 to ~320 putting you on even footing with other champs. Also 1 of these plus FoN puts you right at the cap before the 20% run speed diminishing return.

After this is personal preference

I feel that I'm takny enough with this build without tank quints. Movement speed is always good, and the AS further increases your damage making you less ignorable.

Mastery

[mastery=nimbleness]Only take this if you use [rune=greater seal evasion], otherwise its just not worth taking for the 2% chance.

[mastery=harden skin] This is actually better than it looks since the -damage is taken AFTER resistances. For this build you have about 70% physical damage reduction meaning that even someones with 300 AD is going to only be hitting you for 90 damage. This means that every point actually lowers their attack damage by more than a full 1%.

Offense:
The only thing you lose from the offense tree is [mastery=archaic knowledge] This is not as big of a deal as people think for cho. 15% of MR can be almost nothing vs squishies and against tanks your damage isn't going to be noticeable anyhow.

Defense:
you still gain the resistances.

You lose
-2% dodge
-64 HP is like taking a bucket of water out of the ocean for cho, after early game you wont miss it.
-Ardor the AS can be made up for by quints the AP isnt even noticeable, 2.6 with this build.
-5% damage reduction, yeah this one sucks to lose.

You gain
-Improved flash and ghost along with 15% lower cooldowns.
-6% regens which actually works very will with [item=Force of nature]
-lower dead time (i know it's not the best but I like it better than the alternatives)
-mp5 which helps in early lane.
-Movement speed, this is really good saves your quints for something else. This also adds to you base speed so the added speed is effected by your FoN and ghost.
-CDR is 3% more which is twice as good as what you had through offense.

Cho Damage Math

Why is this in a tank guide?
Anyone who plays Cho knows that all too often once your abilities are on cooldown you get ignored and the other team runs right for your squishies. This is because Cho is so hard to take down and after his spells are on cooldown he doesn't do enough damage to be a threat to anyone.

It is because of this that I feel that it's best to take 1 item to boost your damage to the point where you're either not ignorable or at very least to make them pay the price for ignoring you.

Nashor's Tooth
After a bit of theory crafting I have found that this is the best option for a bunch of reasons.

AS:
Cho has the highest base AD of any champ I've seen (130). On top of this you add another 74 AOE damage from Vorpal Spikes. To give a frame of refrence this is the single target damage of an Lv 18 Master Yi auto attack with wuju popped and a pickaxe with the vorps doing aoe.

This also lets you clear minions easily without wasting mana on Q+W so rather than lose mana, you gain it back with your passive.

AP:
All your spells hit harder.

CDR:
Cuts the time between feasts making it short enough to be ready for every team fight. Also lets your re-stack after a death much faster. With enough CDR you can also get off a Rupture to open a team fight and to catch a runner or help you flee at the end.

Mana/5:
Keeps cho from going OOM.

Comparison: Why you don't go AP for damage.

I'll use 80 AP since it's this is the ap from both Rylai's and RoA which are common items listed in guides.

The difference in ap vs Nashor's is 25
The combined scaling of your Q,W,R is 2.2 giving you a grand total of a 55 extra damage over the course of all your spells in a rotation.

Now lets say that you even manage to hit ALL 5 enemies with BOTH your AOEs (which will never happen).
25*1.7*5= 212.5
As you can see the damage from just 1 more auto attack even if vorpal spikes only hits 1 target is going to make up for the damage you gain from the extra AP even if you hit every enemy with your AOE both times.

While Cho's spells do have high AP raitos it's deceptive since their cooldowns are too long to make AP really effective. In terms of DPS (which means Damage Per Second, not melee damage like some retards on this site think) Cho gets much much more out of AS than AP.

Atma's vs Nashor's

Atmas isn't a terrible choice but whileCho may have a ton of HP but this doesn't make Atmas as good as you may think. The AS with vorpal spikes aoe makes nashor's a better option.

I'll use a generous 5k hp giving you 100 AD with atmas. This is only gives you less than +50% of the damage that you get from your base AD + spike damage (/w AP from nashors). Nashors gives +50% AS and that 50% as effects spikes aoe.

These two things still provided survivability along with more burst damage.
Teams that tend to be more bursty tend to be more AP based so the -20 MR can really help this.

When I do go this route I try to end up with something like this
[builder=Cho'Gath/dd3266f61fa255da7da6bd7951c5a019]

This is a good balance of tanky damage with over 12000 EHP along with good burst and good sustained damage good CDR and adequate mana regen. You wont be super tanky but you will be able to take some punishment as well as deal it out.

Cho Tank Math

Cho'gath is a massively tanky champ with the 900 HP from his feast stacks.

The main thing to consider on any tank is effective HP (EHP).
This is the survivability you have when resistances (MR/Armor) are taken into account.

Formula:

Resistance/100+resistance= % reduction
HP*(1+% reduction)= EHP

Armor EHP + MR EHP /2 = overall EHP.

The way it works out the more HP you have the more resistance increase your EHP and the more resistance you have the more HP will increase your EHP.

Because Cho'Gath has such high base HP from his feast stacks this makes Armor/MR much more effective at raising his EHP than other champs.

Why I don't get....

[item=Rylia's scepter]
All of chos spells excecpt for his ult are AOE and there for only get 15% Slow effect.
AP doesn't increase Cho's damage enough to justify this item.
Hp is nice but doesn't provide the survivability of other items.

Guardian Angel
Decent item on Cho, allows him to save stacks after if he can get away after he revives.

VS Aegis:
-Less MR than Aegis
-More armor but cho already has much higher armor than MR
-Higher price
-Loses the aura, people are already trying to ignore you for your team mates, might as well help em out with this
-The swirly white fog around you gives the other team even more of a reason to ignore you for your team mates.
-The revive effect often times means that you are just going to get dropped again when you revive. If they decided to kill you it usually means that there was no one else to kill leaving them on top of your corpse ready to knock you back into the dirt.
-The revive effect has a long cooldown.

This item is still decent and might be worth taking someone else already has Aegis.

Trojan Cho

Cho'Gaths size isn't just cosmetic by standing over your team it makes them very hard if not impossible to target.

Use this to your advantage since its a close to a taunt as you are going to get.

This works especially well for champs that have channeled ults that can be stunned or silenced.

Kat: shunpo you and spin
Nunu: position right under cho's nut sack and ult
Fid: charge under cho and pop out with crow storm.

This can work very well when you are up against teams that have a stun they keep in their pocket to cancel ults that win team fights.

Udyr, Sion, Taric, garen, any single target CC that will cancel an ult can be countered by just standing under cho.

Aoe CC however will not be effected.

Thank You, Come Again!

Criticism is always welcome I'm always willing to learn from those who know more than me and improve. Just be sure to back up what you say with logic and if possible numbers.

If you down rate please say why. If you have a good reason then it's going to be something that I have to look into and change to improve and is much appreciated.